pipeline leak detection

[hoangvantan]

could anybody held me on pipeline leak detection?
WE have a 6" LPG pipeline 25 Km long and have 3 line break valve station, each line break valve equiped with PSL upstream and downstream of the valve. How can I calculate the setting point for these PSL which will close the line break valve when pipeline rupture?

Many Thanks in advance!

 

[abeltio]

What I did on a situation, similar in the problem statement, but the amount of storaged energy you have is several thousand times higher than the one I faced, was:
I considered the first derivative of pressure with time (dp/dt < -10psi/sec) in my case was enough... you may have to model your system and find out if what the correct number should be...
HTH
Saludos.
a.

 

[hoangvantan]

Thank you abeltio!

You know what i did, From the htydraulic calculation i knew the arrival pressure at each location and this will help to determine the set pressure for PSL; for example: the arrivsal pressure at second LBV is 20 Bar and based on this pressure, the set point of the PSL upstream of the 2nd LBV was sellected at 17 bar. therefore, when pressure dropped to 17 bar this PSL shall close the 1st LBV to stop the flow (each LBV also equipped with check valve) and so on for LBV #2 & LBV#3. Please tell me if this will work? Is there any Code/ Standard, which could help?.

This pipeline was design for normal operating pressure of 9.5 Bar (design pressure =49 Bar). now operating pressure increase to 21. 0-25 Bar Pressure gauges are installed at each LBV and from the pipeline surge analysis, the pipeline pressure can go up to 39 bar (when one or some Lbv closed), the 39 bar pressure to be considered as Maximum working pressure?. Do i have to replace all the 0-25 Bar PG installed on the pipeline to a higher range PG (0-50 bar for example?

Thank you!